Method of installing a pump lever in a pump body



Oct. 5, 1965 w. NICHOLAS 3,209,446

METHOD OF INSTALLING A PUMP LEVER IN A PUMP BODY Original Filed May 2, 1960 FIG. 5.

IN V EN TOR. WILL/AM /V/C/-/0L 45,

United States. Patent 1 Claim. 01. 29-401 This application is a division of copending application Serial No. 26,239, filed May 2, 1960, now abandoned.

This invention relates to a method of assemblying fuel pumps and more particularly to a method for the re placement of worn-out pins in fuel pump bodies made of diecast metals, for example, zinc and the like.

Presently known methods of replacing the pins which pivotally support the levers or rocker arms of diaphragm fuel pumps as used in automotive vehicles require the press fitting of a straight pin through assembled parts of the pump; namely, the rocker arm or lever and the diecast body. Thus, in the usual construction, the diecast body has a pair of parallel walls or checks which have co-axial bores and the lever is placed between the checks and has a bore alignable with the co-axial bores. A straight pin is then forced through the aligned bores by press fit and is retained by friction in the cheek bores. Such an arrangement can, in use, fail due to the pin rotating in the cheek bores and working loose after the frictional grip wanes. Thus, the pin can fall out of the pump body entirely and permit the rocker arm to move into the motor crank case and cause considerable damage. Further, a replacement pin of this type must be very accurately sized and selected in order to be insertable by press fit into the cheek bores and be frictionally gripped a suitable amount. However, the diameter of such a pin must not be so great that it will crack the casting when forced into the cheek bores. Selection of such pins is necessarily a slow process and, accordingly, costly.

Another type of replacement pin utilizes an enlarged rivet head at one end and a bored end at the other end, the bored end being usable in the manner of a tubular rivet with a washer placed over it, the bore being flared out in order to lock the pin in place across the checks of the casting. However, such a pin combining an enlarged head at one end with a bore at the other end is costly and difficult to manufacture and still requires a critical press fit.

My invention has for its object the overcoming of the disadvantages of the method of using the pins of the prior art by providing a method of using a pin that can be furnished by centerless grinding and which is usable within a much wider range of cheek bore diameters than the prior art pins.

Another object of my invention is to provide a method of using replacement pin which can be cheaply manufactured and which will effect considerable savings in the number of pump body castings that can be used which have oversized pin holes and which would otherwise have to be scrapped.

A further object of my invention is to provide a method of using a pin that can be sized by being end fed into a centerless grinding.

A still further object of my invention is to provide a method of using a pin that may be manufactured 'out of solid rod or tubing, although solid rod is preferred.

An even further object of my invention is to provide a method of using a pin which may be inserted in place with either no force fit or merely a light force fit.

end.

A detailed description of my invention will now be given in conjunction with the appended drawing, in which:

FIG. 1 is a plan view illustrating the finished pin.

FIG. 2 is a longitudinal cross section.

FIG. 3 is a fragmentary view of a pump housing and pump rocker arm or lever assembled with the use of one of the pins of the invention.

FIG. 4 is a section through 4-4 of FIG. 3; and

FIG. 5 is a fragmentary view of a modified method of flaring the end of the pin to lock into the pump body casting.

Refering to the drawing, FIG. 1, a steel pin 10 is shown which has been prepared with axial blind bores 14 in respective ends and bevelled corners-17 as shown. Such pin has, of course, been severed from solid rod. If severed from tubular rod, no drillings 'of bores 14 would, of course, be necessary. However, solid rod is preferred for strength and rigidity.

Referring to FIG. 2, the pin is shown as having a copper plating 20 at each end portion and it will be understood that the entire pin had been copper plated, but that the intermediate portion, as indicated by the dot-dash lines for the extent of the bracket B, has been ground away. As hereinabove disclosed, such grinding can be accomplished by end feeding the pins into a centerless grinder in accordance with conventional practice. Thus, the portion B of the pin is substantially from end to end except for the chamfered ends, the surfaces of bores 14 remaining plated as well as the chamfers. The final steps in preparation of the pin is to case harden it in accordance with conventional methods. hardening, the intermediate, bracketed area B becomes case hardened while the end portions protected by the copper plating remain soft. While the relationship of the depth of the bores 14 to the length of end portions copper plated is, of course, a matter of choice and may be varied to suit particular pins intended for certain specific pump constructions, the important feature to be understood, however, is the fact that the drilled and tapered or chamfered end portions remain soft in order to effect a suitable degree of flaring thereof for locking the pin. into a pump casting. Thus, as seen in FIGS. 3 and 4, the pin 10 has been put in place in the cheeks 22 of a casing, while a rocker arm 25 is pivotally carried on the pin. The ends of the pin have been flared as clearly shown in FIG. 4 and it will be further noted that the flaring is carried out to a point wherethe material of the cheek, as indicated by the arrow M, has been flared correspondingly. Thus, the contiguous material of the casting is deformed along the pin ends and this deformation locks the pin against axial play. It will also be noted that the end of the pin is substantially flush with the cheek of the casting or the bosses 28 in which the pin ends are disposed. Obviously, both ends of the pin are deformed in the same manner and it will be noted that a pin substantially smaller than the casting holes may be used inasmuch as the flared ends in the cheeks provide rigid bearing support for such pin. In contrast, pins of the prior art would have to be fitted with relative precision to the bores in which they were to be inserted, including such prior art pins as are tubular at one end but have an enlarged head at the other end. This is due to the fact that the end having the enlarged head does not have any support in its respective casting cheek as is effected by the flaring or outward deformation of the tubular It will now be apparent that such change, while simple, affords a great saving not only in the time ordinarily consumed in fitting pins to particular bore sizes, depending on degree of wear of pumps being rebuilt, but also by effecting reuse of pump bodies having consider- Patented Oct. 5, 1965 In the course of such case.

ably enlarged holes, where such reuse would not be possible with any tape of prior art pin.

Referring now to FIG. 5, it will be noted that the pin ends have been flared in a manner as to represent a somewhat elliptical or out of round condition. Thus, deformation of this type guarantees against rotation of the pin in the cheek bores. It will, of course, be appreciated that a wide variety of out of round conditions can be used: for example, an elliptical punch, a triangular punch, a punch having one or more ridges, etc., etc., ad infinitium. Preferably the first time a fuel pump body casting is reused, a round punch is used. However, upon second rebuilding of the pump wherein the pin is replaced, an out of round punch may be used. Thus, since it is assumed that after the second re-use the life of the casting is about gone, it is not necessary to re-align the deforming tool with the position in which the initial forming tool was placed for flaring a pin in the cheek bores for the second time. On the other hand, if an out of round distortion was used in the first replacement then it would, of course, be necessary to orient the same tool in the same position in order to maintain the same out of round on the second replacement.

The advantages of the invention will be apparent. Thus, the cost of the pin is approximately the same as the cost of prior art pins, as is assembly time and cost of assembly. On the other hand, however, by expanding or deforming both ends into the casting body, my pin effects a good sealant for prevention of oil leakage out of the cheek bores, in addition to preventing pin rotation which would cause cheek bore wear. Further, by utilizing a pin which can be placed through the cheek bores with no force fit or preferably with light force fit, shearing of the bores and gouging of the bores is prevented. Thus, in inserting a pin into the cheek bores there is usually a certain amonut of misalignment, and naturally, when a heavy press fit is used, much metal can be sheared from the bores, particularly the second bore entered. This, of course, would aggravate the condition which would permit rotation of the pin even though inserted with a heavy force fit, due to lack of frictional grip of the casting material on the pin by virtue of removal of material of the bore In contiguity with the pin. However, in my novel method of assembling the pin in a pump casting, expansion of the tubular ends tends to compress the diecast material contiguous therewith to thus effect an excellent oil seal, while at the same time increasing the grip of the diecast material on the pin.

It will further be noted that by leaving the copper plating on the end portions of the pin, a soft facing is provided which acts like a seal coating that extrudes into any fine fissures and stretches in the cheek bores to fill them up for further effecting oil seal,

Further, the copper plating on the exposed ends of the pins also cuts down possible rusting thereof.

Finally, the invention contemplates the salvaging of many castings otherwise unuseable due to oversized holes where it would not be economic to make pins large enough to be operable therewith, and also eliminates the usual critical gauging operation generally required for matching pins to cheek bores.

It will, of course, be understood that my invention may be utilized not only in connection with the rebuilding of used fuel pumps, but also in conjunction with new pumps as well and, in fact, the invention is applicable in all applications of rebuilding or new produtcion where precision matching of pins and bores is expensive and time consuming, and where the other advantages pointed out hereinabove would be of importance.

Having thus described my invention, I am aware that various changes may be made without departing from the spirit thereof, and accordingly, I do not seek to be limited to the precise illustration herein given except as set forth in the appended claim.

I claim:

A method of installing a pump lever in a pump body wherein said pump body is made of diecast metal and wherein said lever has a bore and is insertable between a pair of cheeks of said body and wherein said checks have a pair of co-axial bores alignable with the bore of said lever, said method comprising placing a pivot pin through said aligned bores wherein said pivot pin has tubular end portions, flaring the tubular end portions of said pivot pin with a force sufiicient to correspondingly flare the metal of said cheeks contiguous with the flared ends of said pin to lock said pin against axial movement, wherein flaring of the ends of said pins is accompanied by out of round distortion, said contiguous metal of said cheek bores being distored accordingly so as to lock said pin against rotative movement.

References Cited by the Examiner UNITED STATES PATENTS 2,005,087 6/35 Kamack 29-5 12 X 2,060,394 11/36 Hiering 29444 2,260,149 10/41 Meek 29512 X 2,476,151 7/49 Le Jeune 29529 2,646,824 7/53 Johnson.

2,709,848 6/55 Chatfield 29526 2,793,536 5/57 Onulak.

2,881,518 4/59 Toulmin 29527 WHITMORE A. WILTZ, Primary Examiner.

CHARLIE T. MOON, Examiner. 

